Sample cell and probe integrated device for Raman spectroscopy detection

Abstract

The present application discloses a sample pool and probe integrated device for Raman spectrum detection, which is applied to a pressurized water reactor neutron-free radiation source boric acid concentration detector, which includes: a sample pool for holding a solution to be tested; an optical path system, including a closed outer shell and a Raman probe assembly arranged inside the outer shell, the Raman probe assembly is used to emit a laser beam; a flange window, the flange window is arranged between the outer shell and the sample pool, the outer shell is connected to the sample pool through the flange window, and the laser beam acts on the solution to be tested through the flange window; wherein a planar super lens is arranged between the Raman probe assembly and the sample pool, the planar super lens is fixedly mounted on the flange window, the planar super lens acts on the laser beam so that the laser beam is focused and then acts on the solution to be tested to form a Raman scattering signal, and the pressure resistance of the planar super lens is not less than 3 MPa. Through the above arrangement, the loss generated during the light transmission process is reduced to improve the intensity of the Raman signal.

Description

Technical Field

[0001] The present application relates to the technical field of pressurized water reactor analysis, and in particular to a sample cell and probe integrated device for Raman spectroscopy detection. Background Art

[0002] Since Raman spectroscopy has the ability to identify the "fingerprint" characteristics of materials, the use of Raman spectroscopy technology for real-time in-situ detection of solutions or gas pipelines can provide companies with richer monitoring information, including material types, material content, and changes in material molecules.

[0003] In the nuclear industry and other fields, in order to realize online real-time monitoring of Raman spectroscopy, the required optical window is made on the pipeline for transporting the object to be detected, and the Raman laser beam is introduced into the pipeline through the optical window to excite the Raman signal of the material in the pipeline. The excited Raman signal is then collected and analyzed through the optical window. This is the necessary optical signal excitation and collection method for obtaining Raman scattering signals in the current online monitoring process.

[0004] For traditional Raman spectroscopy systems, convex lenses are usually used as focusing optical elements to focus the incident laser on the substance to be tested to obtain a strong Raman light signal. For the online real-time detection system of solutions using Raman spectroscopy technology, since the convex lens can only be used as a focusing optical element, it cannot be used as a mechanical structural element that contacts the solution and realizes the functions of solution isolation and pipeline pressure resistance. Therefore, in the relevant technology, the detection system needs to realize the two types of functions through different elements, such as using a planar pressure-resistant optical window as a light-transmitting medium to contact the solution and withstand pressure, and at the same time as a laser transmission channel for exciting Raman light; using a convex lens as a focusing element to focus the incident laser, and through the optical window in contact with the solution, the laser is focused into the solution to excite the Raman light signal. This method will inevitably introduce multiple optical interfaces, resulting in light loss. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the purpose of the present application is to provide a sample cell and a probe integrated device for Raman spectroscopy detection that can improve the stability of Raman scattering signals.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] A sample cell and probe integrated device for Raman spectrum detection, applied to a boric acid concentration detector for a pressurized water reactor neutron-free radiation source, comprising:

[0008] A sample pool, used to hold the solution to be tested;

[0009] The optical path system comprises a closed outer shell and a Raman probe assembly arranged inside the outer shell, wherein the Raman probe assembly is used to emit a laser beam;

[0010] A flange window is provided between the outer shell and the sample cell. The outer shell is connected to the sample cell through the flange window. The laser beam passes through the flange window and acts on the solution to be tested.

[0011] Among them, a planar superlens is provided between the Raman probe assembly and the sample cell. The planar superlens is fixedly mounted on the flange window. The planar superlens acts on the laser beam so that the laser beam is focused and then acts on the solution to be tested to form a Raman scattering signal. The pressure resistance of the planar superlens is not less than 3 MPa.

[0012] Furthermore, the surface of the planar superlens has a micro-nanohole structure so that the phase of the laser beam is sequentially changed from the center point of the planar superlens to its edge.

[0013] Furthermore, the substrate material of the planar superlens includes at least one of the following materials: quartz, sapphire, aluminum oxynitride, and calcium fluoride.

[0014] Furthermore, the planar metalens is a high numerical aperture focusing objective lens, and the aperture of the high numerical aperture focusing objective lens is greater than or equal to 0.1 and less than or equal to 0.45.

[0015] Furthermore, the diameter of the high numerical aperture focusing objective lens is greater than or equal to 2 mm and less than or equal to 40 mm.

[0016] Furthermore, the focal length of the planar metalens is greater than or equal to 1 mm and less than or equal to 10 mm.

[0017] Furthermore, the thickness of the planar metalens is greater than or equal to 1 mm and less than or equal to 5 mm.

[0018] Furthermore, the optical path system also includes a signal sampling unit for receiving the Raman scattering signal. The Raman probe assembly receives the Raman scattering signal and transmits the Raman scattering signal to the signal sampling unit. The signal sampling unit generates a Raman spectrum based on the Raman scattering signal, wherein the Raman spectrum covers an interval characterizing a characteristic peak of boric acid.

[0019] Furthermore, the pressurized water reactor neutronless radiation source boric acid concentration detector also includes a signal processing system for determining the boric acid concentration in the solution to be tested according to the interval of the boric acid characteristic peak.

[0020] Furthermore, the signal sampling unit includes a spectrometer and a CCD camera. The spectrometer receives the Raman scattering signal and images the Raman scattering signal into a Raman spectrum. The CCD camera samples the Raman spectrum and transmits the sampled Raman spectrum to the signal processing system.

[0021] Compared with the prior art, the sample cell and probe integrated device for Raman spectroscopy detection forms a Raman scattering signal by arranging a planar superlens between the Raman probe assembly and the solution to be tested, focusing the laser beam through the planar superlens and then acting on the solution to be tested. This can effectively reduce the deviation of the laser beam during the focusing process and reduce reflection loss, thereby improving the stability and accuracy of the Raman scattering signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of an optical window in the prior art;

[0023] Figure 2 This is a schematic diagram of a boric acid concentration detector for a pressurized water reactor neutronless radiation source in an embodiment of the present application;

[0024] Figure 3 This is a schematic diagram of a metasurface lens in an embodiment of the present application;

[0025] Figure 4 This is a comparison chart of the spectrum collected by the Raman system integrating the superlens and the flange window in the embodiment of the present application and the spectrum collected by the traditional Raman system;

[0026] Figure 5 Schematic diagram of a signal processing system in an embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the specific implementation manner of the present application will be clearly and completely described below in conjunction with the drawings in the implementation manner of the present application.

[0028] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0029] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0030] like Figure 2As shown, the present application provides a sample pool and probe integrated device 100 for Raman spectroscopy detection, which is applied to a boric acid concentration detector for a pressurized water reactor neutron-free radiation source. Pressurized water reactors are a type of reactor with a large number of applications and a large capacity in nuclear power plants. The full name is "pressurized water moderated cooled reactor", which uses pressurized, non-boiling light water as a moderator and coolant. Pressurized water reactor nuclear power plants include several circulation loops, and boric acid is added to the circulation loop as the main neutron absorber to absorb neutrons in fission reactions, thereby adjusting the chain reaction rate of cadmium control rods. By monitoring the boric acid concentration in the coolant of the circulation loop, the reactivity of the core can be known and regulated. Therefore, pressurized water reactor nuclear power plants need to monitor the boric acid concentration in the circulation loop in real time.

[0031] As an implementation method, the sample cell and probe integrated device 100 for Raman spectroscopy detection includes:

[0032] The sample pool 11 is used to hold the solution to be tested (i.e., the coolant mentioned above). The sample pool 11 is connected to a circulation loop. The sample pool 11 has at least one inflow end and an outflow end. The solution to be tested in the circulation loop enters the sample pool 11 from the inflow end and flows out of the sample pool 11 along the outflow end, so as to realize real-time dynamic detection of the boric acid concentration in the solution to be tested.

[0033] The optical path system 12 comprises a closed outer shell and a Raman probe assembly 122 disposed inside the outer shell 121. The Raman probe assembly 122 is used to emit a laser beam, and the laser beam is applied to the solution to be tested so that the solution to be tested forms a Raman scattering signal.

[0034] The Raman probe assembly 122 at least includes a laser 1221, a Raman probe 1222, and several optical elements (not shown). The laser 1221 is used to generate a laser beam, which passes through the Raman probe 1222 along a set direction, and changes the propagation path of the laser beam through the optical lens in the Raman probe 1222, so that the laser beam is emitted from the outer shell 121 along the set direction. The Raman probe 1222 is also used to receive Raman scattering signals and propagate the Raman scattering signals along the set direction through the optical elements. The optical element can be an optical lens.

[0035] The flange window 13 is arranged between the outer shell 121 and the sample pool 11. The two ends of the flange window 13 are fixedly connected to the outer shell 121 and the sample pool 11 respectively. The outer shell 121 is connected to the sample pool 11 through the flange window 13, so that the laser beam emitted by the Raman probe 1222 can reach the solution to be tested in the sample pool 11 through the flange window 13.

[0036] like Figure 3As shown, a planar superlens 14 is further provided between the Raman probe assembly 122 and the sample pool 11. The planar superlens 14 is fixedly mounted on the flange window 13 so that the planar superlens 14 isolates the space between the sample pool 11 and the outer shell 121. The planar superlens 14 acts on the laser beam so that the laser beam is focused and then acts on the solution to be tested to form a Raman scattering signal. The pressure resistance of the planar superlens 14 is not less than 3 MPa.

[0037] As a new type of optical element, the main advantage of superlens in early applications is that it can achieve imaging resolution that exceeds the diffraction limit of traditional optics. Traditional convex lenses are limited by the wavelength of light waves and cannot distinguish two points that are too close, which is the so-called diffraction limit. Superlenses can overcome this limitation, making imaging at the nanoscale possible. Superlenses mainly use the microscopic structural units (meta-surface elements) on the surface to accurately control the phase of the incident light, achieve high-precision control of the light wavefront, and achieve the deflection of light at different positions through the control of the wavefront, ultimately achieving the focusing function.

[0038] According to the focusing principle of the above-mentioned superlens, the superlens can be designed as a planar pressure-resistant structure. It should be noted that the sample pool and probe integrated device for Raman spectroscopy detection provided by this application are applied to the boric acid concentration detector of the neutron-free radiation source of the pressurized water reactor. The planar superlens has a pressure resistance of not less than 3 MPa, and can be in contact with the solution in the high-pressure detection environment of the pressurized water reactor, and serve as a mechanical structural element to achieve solution isolation and pipeline pressure resistance. This application realizes the focusing function through the design of the superlens while taking into account the mechanical capacity of the optical window, thereby integrating the functions of two discrete optical elements in the Raman spectroscopy real-time detection system of the online solution, thereby improving the collection efficiency and sensitivity of the Raman optical signal.

[0039] The planar metalens 14 has the advantages of being thinner, lighter, lower cost, better imaging, and easier to integrate. In addition, the properties of light such as polarization, phase, and amplitude can be controlled by adjusting the shape, rotation direction, height, and other parameters of the structure.

[0040] Since the Raman scattering signal is extremely weak and extremely sensitive, any change in the optical path, material environment, and temperature will have a significant impact on the intensity of the Raman spectrum, resulting in a large detection error in the quantitative detection of the Raman spectrum. In the example of the present application, by setting a planar superlens 14 to reduce the number of elements between the Raman probe assembly 122 and the solution to be tested, the loss of the laser beam when passing through the optical element during the transmission process is reduced, thereby improving the stability and accuracy of the Raman scattering signal.

[0041] Specifically, Figure 4As shown, it shows a comparison of the spectrum collected by the Raman system integrating the super lens and the flange window in the embodiment of the present application and the spectrum collected by the traditional Raman system. Figure 4 It can be seen that at wave number 400cm -1 and 650cm -1 The peak intensity measured by the Raman system with the integrated superlens and flange window provided by the present application is higher than that of the traditional Raman system. The Raman system with the integrated superlens and flange window provided by the present application can reduce the loss of the laser beam when it passes through the optical element during transmission, thereby improving the stability and accuracy of the Raman scattering signal.

[0042] As an implementation method, by selecting the surface phase distribution of the planar metalens 14 and the geometric design of the nanoscale structure, when the laser beam passes through the planar metalens 14, the phase of the laser beam is changed sequentially from the center point of the planar metalens 14 to its edge.

[0043] The phase control of the planar metalens 14 is as follows:

[0044] Resonant phase control, which achieves phase mutation by changing the resonant frequency, which is controlled by the geometry of the nanoscale structure;

[0045] Propagation phase control: Since electromagnetic waves will produce optical path difference during propagation, this characteristic can be used to achieve phase control;

[0046] Geometric phase control achieves phase mutation of light waves by adjusting the rotation angle of micro-nanostructures of the same size, thereby realizing artificial control of phase gradient or distribution, thus greatly reducing the complexity of designing and processing metasurfaces.

[0047] In the example of the present application, the surface of the planar metalens 14 has a micro-nanopore structure, and the phase of the laser beam is changed by geometric phase control. Since the geometric phase control is not affected by material dispersion, structural size and structural resonance, the structural strength of the planar metalens 14 can be improved, and the planar metalens 14 can select a substrate material with higher corrosion resistance.

[0048] Since the metasurface lens is disposed between the sample pool 11 and the outer shell 121, the space of the sample pool 11 and the space of the outer shell 121 are isolated only by the metasurface lens. In order to prevent the pressure generated during the circulation of the test solution from damaging the metasurface lens, or the test solution from corroding the metasurface lens, the base material of the planar metalens 14 needs to meet certain pressure resistance and corrosion resistance requirements.

[0049] As an implementation manner, the substrate material of the planar superlens 14 includes at least one of the following materials: quartz, sapphire, aluminum oxynitride, and calcium fluoride.

[0050] Optionally, the base material of the planar superlens 14 may also include titanium dioxide, silicon nitride, gallium nitride, etc.

[0051] As an implementation method, the planar superlens 14 includes an achromatic superlens, a high numerical aperture superlens, a super-resolution planar superlens, and an infrared superlens. In the example of the present application, the planar superlens 14 uses a high numerical aperture superlens, and the aperture of the high numerical aperture superlens is greater than or equal to 0.1 and less than or equal to 0.45. Further, the diameter of the high numerical aperture superlens is greater than or equal to 0.22 mm and less than or equal to 0.45. More preferably, the aperture of the high numerical aperture superlens is greater than or equal to 0.3 and less than or equal to 0.45. It should be noted that the numerical aperture is a dimensionless number used to measure the angle range of the laser beam that the planar superlens 14 can collect. If the numerical aperture is larger, the planar superlens 14 can collect more light and the resolution is higher. Through the above-mentioned setting, it is avoided that the numerical aperture of the planar superlens 14 is too small, resulting in a low Raman scattering signal generated by the laser beam acting on the solution to be tested, and at the same time, it is avoided that the numerical aperture of the planar superlens 14 is too large to affect the focusing effect of the planar superlens 14.

[0052] The two optical elements are integrated into one optical element by replacing the double-cemented lens used for focusing in the traditional design with a planar superlens 14. The traditional lens is restricted by the refractive limit in optical imaging, that is, the laser beam cannot be focused to a size smaller than the wavelength, which limits the resolution of the optical system.

[0053] As an implementation method, the focal length of the planar metalens 14 is greater than or equal to 1 mm and less than or equal to 10 mm. Further, the focal length of the planar metalens 14 is greater than or equal to 5 mm and less than or equal to 10 mm. More preferably, the focal length of the planar metalens 14 is greater than or equal to 7 mm and less than or equal to 9 mm. Through the above arrangement, the laser beam can be focused to a size smaller than its wavelength, thereby improving the resolution of the optical system.

[0054] According to the above content, the substrate material of the planar metalens 14 includes quartz, sapphire, aluminum oxynitride, calcium fluoride, etc., and the above substrate materials have high hardness. Therefore, compared with the double glued lens for focusing in the traditional design, the size of the planar metalens 14 can be designed to be smaller and thinner. Since the Raman scattering signal is extremely weak and extremely sensitive, the loss generated during the refraction of the laser beam is avoided to ensure the accuracy of the Raman scattering signal.

[0055] As an implementation method, the thickness of the planar superlens 14 is greater than or equal to 1 mm and less than or equal to 5 mm. Further, the thickness of the planar superlens 14 is greater than or equal to 3 mm and less than or equal to 5 mm. More preferably, the thickness of the planar superlens 14 is greater than or equal to 3 mm and less than or equal to 4 mm. Through the above arrangement, it is possible to avoid the thickness of the planar superlens 14 being too large, resulting in a large optical loss during the refraction of the laser beam, thereby ensuring the accuracy of the Raman scattering signal; at the same time, it is also possible to avoid the thickness of the planar superlens 14 being too small, resulting in a reduction in its refractive index and affecting the focusing effect.

[0056] As an implementation method, the optical path system 12 also includes a signal sampling unit 123, which is installed in the outer shell 121 and is used to receive the Raman scattering signal. The laser beam is focused by the planar metalens 14 and acts on the solution to be tested to form a Raman scattering signal. The Raman probe assembly 122 receives the Raman scattering signal and transmits the Raman scattering signal to the signal sampling unit 123.

[0057] like Figure 5 As shown, specifically, the signal sampling unit 123 includes a spectrometer 1231 and a CCD camera 1232. The spectrometer 1231 is used to receive Raman scattering signals. The Raman scattering signals can be imaged on the spectrometer 1231 and form a Raman spectrum. The CCD camera 1232 captures the Raman spectrum imaged by the spectrometer 1231 and sends it to the signal processing system 200.

[0058] The Raman spectrum covers an interval representing a characteristic peak of boric acid, and the signal processing system 200 determines the concentration of boric acid in the solution to be tested according to the interval of the characteristic peak of boric acid.

[0059] Exemplarily, the signal processing system 200 includes a portable device, which is electrically connected to the laser 1221 and the CCD camera 1232. When the solution to be tested flows through the sample pool 11, the portable device is controlled to send a detection signal to the laser 1221 to drive the laser 1221 to work. The laser 1221 emits a laser beam of a set frequency, and the laser beam acts on the solution to be tested through the Raman probe 1222 and the metasurface lens, and generates a Raman scattering signal. The Raman probe 1222 obtains the Raman scattering signal and sends the Raman scattering signal to the spectrometer 1231 to form an image on the spectrometer 1231 and form a Raman spectrum. The CCD camera 1232 captures the Raman spectrum imaged by the spectrometer 1231 and encapsulates it into a data signal representing the Raman spectrum. The portable device obtains the data signal, performs corresponding processing on the data signal, and displays it on its interface.

[0060] In some other examples, the signal processing system 200 further includes a fixed terminal, which is connected to the portable device, wherein the connection between the fixed terminal and the portable device includes an electrical connection and an optical fiber connection. The portable device can synchronize the data signal to the fixed terminal to perform corresponding display on the interface of the fixed terminal.

[0061] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to this application.

Claims

1. A sample cell and probe integrated device for Raman spectroscopy detection, applied to a pressurized water reactor neutron-free radiation source boric acid concentration detector, characterized in that: include: A sample pool, used to hold the solution to be tested; An optical path system comprises a closed outer shell and a Raman probe assembly arranged inside the outer shell, wherein the Raman probe assembly is used to emit a laser beam; A flange window, wherein the flange window is disposed between the outer shell and the sample pool, the outer shell is connected to the sample pool through the flange window, and the laser beam acts on the solution to be tested through the flange window; A planar superlens is provided between the Raman probe assembly and the sample pool, the planar superlens is fixedly mounted on the flange window, the planar superlens acts on the laser beam so that the laser beam is focused and then acts on the solution to be tested to form a Raman scattering signal, the pressure resistance of the planar superlens is not less than 3 Mpa, and the thickness of the planar superlens is greater than or equal to 1 mm and less than or equal to 5 mm; the planar superlens is a high numerical aperture superlens, and the diameter of the high numerical aperture superlens is greater than or equal to 1 mm and less than or equal to 40 mm, wherein the substrate material of the planar superlens includes at least one of the following materials: quartz, sapphire, aluminum oxynitride, and calcium fluoride.

2. The sample cell and probe integrated device for Raman spectroscopy detection according to claim 1, characterized in that: The surface of the planar superlens has a micro-nano hole structure, so that the phase of the laser beam is sequentially changed from the center point of the planar superlens to the edge thereof.

3. The sample cell and probe integrated device for Raman spectroscopy detection according to claim 1, characterized in that: The aperture of the high numerical aperture superlens is greater than or equal to 0.1 and less than or equal to 0.

45.

4. The sample cell and probe integrated device for Raman spectroscopy detection according to claim 1, characterized in that: The focal length of the planar metalens is greater than or equal to 1 mm and less than or equal to 10 mm.

5. The sample cell and probe integrated device for Raman spectroscopy detection according to claim 1, characterized in that: The optical path system further includes a signal sampling unit for receiving the Raman scattering signal. The Raman probe assembly receives the Raman scattering signal and transmits the Raman scattering signal to the signal sampling unit. The signal sampling unit generates a Raman spectrum according to the Raman scattering signal.

6. The sample cell and probe integrated device for Raman spectroscopy detection according to claim 5, characterized in that: The PWR neutronless radiation source boric acid concentration detector also includes a signal processing system. The Raman spectrum covers an interval characterizing a characteristic peak of boric acid. The signal processing system is used to determine the boric acid concentration in the solution to be tested according to the interval of the characteristic peak of boric acid.

7. The sample cell and probe integrated device for Raman spectroscopy detection according to claim 6, characterized in that: The signal sampling unit includes a spectrometer and a CCD camera. The spectrometer receives the Raman scattering signal and images the Raman scattering signal into the Raman spectrum. The CCD camera samples the Raman spectrum and transmits the sampled Raman spectrum to the signal processing system.

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